Our group investigates phase
transitions in condensed matter, using neutron scattering in most of our
Our main research interest is the study of
phase transitions in condensed matter. Of particular interest are phase
transitions in which the ordered phase does not occur until zero Kelvin, the
so-called quantum phase transitions. These transitions are different from
'classical' phase transitions in the sense that quantum fluctuations are
more important than thermal fluctuations, resulting in a new type of
ordering behavior. These transitions are primarily studied by means of
neutron scattering experiments, and by susceptibility and transport
measurements. We have two pet systems: CeRuFeGe and lithium-based spinels.
We are also investigating why liquid metals
behave so differently from non-metallic liquids. In particular, we have been
looking at the magnetic properties of some of these non-magnetic liquids,
and found that magnetic interactions are actually quite important on short
Together with Robert McQueeney and Mohana
Yethiraj, we have been studying the Verwey transition in magnetite. We have
looked into the old problems and discovered some new effects.
Finally, we are continuing the study of the superfluid phase of liquid helium, a phase in
which the fluid has zero viscosity.
We do our neutron scattering work at the
Missouri Research Reactor, and at national labs all over. We are working on
an electronic course in neutron scattering, and on a web manual that
explains the intracies involved with neutron scattering experiments.
Together with Bruce McClure and Marc Johnson
we are running an outreach program called Saturday Morning Science. It is a
series of weekly science talks intended for high school students and for
anyone who has some interest in science. We are in our13th season
now, and the talks are attended by about 100-150 people each Saturday (18,000
total during the first twelve seasons).
A textbook on liquids has been completed,
entitled "Excitations in simple liquids, liquid metals and superfluids"
which is due to appear September 2010 with Oxford University Press.